The apparatus of the present invention relate to a means for extracting juice from plant materials such as fruits and vegetables. Numerous devices have been developed in the past for centrifugally separting the juice component of a plant material from the pulp component. An example of such a device is that disclosed in Weston U.S. Pat. No. 2,295,922. Generally these known devices comprise a rotating disc or plate surrounded by a similarly rotating filter element. A plant material brought into contact with the disc is shredded into small particles by cutting elements forming a part of the disc and then thrown outwardly by centrifugal force to impinge upon the surrounding filter. The pulp component of the shredded material is captured by the filter while the juice component is permitted to pass through and be collected for subsequent conduction to the exterior of the device.
The rotating discs or other means utilized by known prior art devices to shred the plant material generally contain or embody cutting blades, wire mesh, or a series of apertures with upstanding margins. In any case, the function of the disc is to reduce the incoming plant material to small bits or particles that are then thrown against the rotating filter for separation into juice and pulp.
A significant disadvantage of known prior art devices is that, because of the cutting or grating action of their rotating discs, the plant material leaves the disc and impinges upon the rotating filter in the form of pulp containing a substantial proportion of material that has been merely cut or sliced into small chunks of the incoming whole, rather than being pulverized into a relatively uniform mixture of juice and well-beaten pulp. This less-than-complete pulverization of the incoming material produces a mixture having a significant amount of juice-containing particles that cannot be effectively treated by the rotating filter. The result is that a substantial proportion of the juice that could otherwise be extracted from the plant material is discarded with the pulp when the device is cleaned.
An additional disadvantage of the known prior art devices is that the pulp material impinging upon the interior surface of the rotating filter tends to accumulate after a period of time into a fairly thick mass that restricts the flow of juice through the filter. This pulp accumulation over the surface of the filter requires that the device be stopped often and the pulp material removed, either by removing a filter liner separating the pulp from the rotating filter element or by removing and cleaning the filter element itself. Also, because the pulp material tends to accumulate over the surface of the rotating filter in a nonuniform manner, the dynamic balance of the device may be adversely affected, causing the device to vibrate. Once such vibration begins, often without warning, the device must be immediately shut down and the accumulated pulp material removed or the device will be damaged.
A further disadvantage of known prior art devices, especially those devices utilizing a bladed member to convert the plant material into a pulp and juice mixture, is that their bladed or other cutting and slicing elements must be periodically sharpened, an operation generally requiring the device to be shut down for a significant period of time with an attendant decrease in production efficiency.
Finally, cleaning of pulp from known prior art devices after the extraction of juice from the pulp generally requires stopping the device and disassembly components thereof, which is time-consuming and impedes juice production.
Thus there remains a need for a juice extractor capable of completely pulverizing a plant material into its pulp and juice components so as to maximize the extraction of the juice from the pulp, as well as for a device that provides self-cleaning of the filter element, does not require sharpening, and may be emptied of accumulated pulp material without requiring a cessation or significant interruption of operation.